condition mean min max ZT0-3 18.83341666666667 16.47025 22.0849 ZT4-7 17.009500000000003 17.009500000000003 17.009500000000003 ZT8-11 21.64375 21.64375 21.64375 ZT12-15 35.581625 33.7195 37.44375 ZT16-19 33.0742 33.0742 33.0742 ZT20-23 28.31785 28.31785 28.31785